JPH07120511B2 - Color picture tube - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a color image of a type in which a shadow mask is fixed to a peripheral frame mounted at a certain distance from a cathode ray emission (cathode luminescence) screen. BACKGROUND OF THE INVENTION This invention relates to tubes, and more particularly to a novel mask-frame assembly for such video tubes.

BACKGROUND OF THE INVENTION The accuracy with which an electron beam emitted from an electron gun hits an individual cathode ray emitting screen element area depends on the accuracy of the alignment between the aperture of the shadow mask and the screen element area during operation of the picture tube. It depends largely on the accuracy. During start-up of the picture tube, the shadow mask is heated by the impact of the electron beam at a much faster rate than the heavier peripheral frame. Due to insufficient heat conduction to the peripheral portion of the mask, the perforated portion of the shadow mask expands at a faster speed than the peripheral portion of the mask. Since the peripheral portion of the mask acts as a low temperature zone surrounding the perforated portion, the perforated portion rises in a dome shape. When such ridges occur, the electron beam passing through the shadow mask will be misaligned with the associated screen element area, resulting in an unwanted color shift on the screen.

The majority of current color picture tube formats are such that the peripheral frame is suspended within the faceplate panel by springs welded directly to the peripheral frame or welded to a plate welded to the peripheral frame. is there. In the direct welding method, the spring is made of bimetallic metal, and in the method of welding to the plate material, the plate material is made of bimetal material. As the spring or plate is heated by heat conduction from the shadow mask to the peripheral frame, the two materials that make up the bimetal exhibit different expansion, which causes the spring or plate to bend and the mask-frame assembly to form a screen for the picture tube. Move towards.

Mask inside the rectangular faceplate panel of the picture tube
Usually three or four springs are used to support the frame structure. In the method of supporting by three springs, one spring is usually arranged at the center of the upper edge of the mask, and the other two springs are respectively arranged along the sides of the picture tube and the center of the mask side and the mask. It is arranged between the lower corner. In the method of supporting with four springs,
Usually, they are arranged at the center of the upper and lower end edges and the center of the left and right side edges of the mask, respectively. Regardless of which of the above two supporting methods is adopted, the mask-frame structure may be slightly rotated (twisted) during the operation of the picture tube and may be displaced with respect to the face plate.

Accordingly, there is a need to develop a video tube having a mask-frame structure support system that can be assembled economically while minimizing the problems of dome-shaped protrusion, rotation and displacement of the mask. To meet.

[Outline of Invention]

The shadow mask type color picture tube according to the present invention has an improved mask-frame structure. The frame has two first and second flanges extending in a cross-sectional shape orthogonal to each other. The first flange (36 in the example below) extends from the second flange (38 in the example below) in a direction substantially parallel to the central longitudinal axis of the picture tube (ZZ in the example below). ing. Also, the second flange, so as to be substantially orthogonal to the surface of the first flange,
Further, it extends toward the central longitudinal axis of the picture tube in a direction substantially parallel to the surface of the shadow mask. The second flange is provided with a plurality of tabs on its inner edge. The tabs are spaced from each other and extend from the inner edge in a direction substantially parallel to the central longitudinal axis of the picture tube. The shadow mask is attached to and supported by the frame by mechanically contacting the plurality of tabs and being fixed (for example, welded) to some of the tabs. In the preferred embodiment, the corners of the frame are truncated (truncated). A spring is interconnected with each of these frusto-conical corners of the frame to mask within the picture tube.
It supports the frame structure.

[Detailed description of the preferred embodiment]

FIG. 1 shows a rectangular color picture tube 8 having a glass envelope 10. The envelope 10 is composed of a rectangular face plate panel 12, a tubular neck portion 14 and a rectangular funnel 16 connecting them, and the panel 12 is sealed by a face plate 18 and a funnel 16 for observation. It consists of a peripheral flange or side wall 20. Panel 12
Has two axes orthogonal to each other, that is, a long axis XX parallel to the wide dimension direction (usually the horizontal direction) and a short axis YY parallel to the narrow dimension direction (usually the vertical direction).
Both the long axis and the short axis are orthogonal to the central longitudinal axis Z-Z of the picture tube passing through the center of the neck portion 14 and the center of the panel 12. A mosaic-shaped three-color phosphor screen 22 is held on the inner surface of the face plate 18. The screen 22 is preferably a linear screen in which phosphor lines extend substantially parallel to the short axis Y-Y, but it may be a dot screen. A shadow mask 24, which is a porous color selection electrode, is removably mounted at a predetermined distance from the screen 22 by the novel means of the present invention. Electron gun 26
Is mounted on its central axis in the neck and
The electron beams of the book are generated, and these are projected along the concentrated path through the mask 24 toward the screen 22.

The picture tube of FIG. 1 is designed for use with an external magnetic deflection yoke, such as yoke 28 located near the funnel-neck junction. The deflection yoke 28, when energized, causes a magnetic field to act on the three electron beams, which causes them to scan the screen 22 horizontally and vertically to form a rectangular raster.

The shadow mask 24 is part of the novel mask-frame structure 30, which also includes a peripheral frame 32. The mask-frame assembly 30 is shown in FIGS. 1, 2 and 3 as being disposed within the panel 12. The mask-frame assembly 30 is attached to the panel 12 by the support means 34 shown in FIGS. 3, 4 and 5. A frame 32 seen from three different directions is shown in FIGS. 6, 7, and 8, and a cross section thereof is shown in FIGS. 9 and 10.

The frame 32 includes two flanges, that is, a first flange and a first flange, which are connected to each other in a substantially orthogonal relationship so as to form an L-shaped section.
Flange 36 and a second flange 38. The first flange 36 extends from the second flange 38 in a direction substantially parallel to the central longitudinal axis ZZ of the picture tube 8. The second flange 38 is inwardly directed toward the central longitudinal axis ZZ of the picture tube 8 in a direction substantially perpendicular to the surface of the first flange 36 and in a direction substantially parallel to the surface of the mask 24. Extending from the first flange 36. At the distal end or inner edge of the second flange 38 (in the illustrated example, the edge farther from the first flange), the central longitudinal axis Z--Z of the picture tube 8 is substantially located at positions separated from each other on the peripheral edge thereof. The four corners 42 of the frame 32 that extend in the parallel direction have a truncated shape (a truncated shape), and are substantially perpendicular to the diagonal direction of the frame.

The mask-frame structure support means 34 has a support structure provided at each of the four corners of the frame and the panel. Each support structure comprises a stud 44, a spring 46 and a bimetal plate 48. Each stud 44 is a hollow conical metal member embedded in the sidewall 20. Each bimetal plate 48 is
It is welded to the first flange 36 at the position of the truncated corner 42 of the frame 32, and extends toward the face plate 18 with the low expansion coefficient side thereof facing the stud 44. Each spring 46
After being welded to the bimetal plate 48, one end thereof is bent backward about 22 degrees. An opening 50 near the free end of each spring 46 engages the conical tip of stud 44.

As shown in FIGS. 1, 2 and 3, the shadow mask 24 includes a curved perforated portion 25, a non-perforated edge portion 27 surrounding the perforated portion 25, and the non-perforated edge portion 27. There is a skirt portion 29 that bends backward and extends away from the screen 22. The mask 24 fits within the frame 32 and the tab 40
There is mechanical contact with the frame 32 only at. mask
The 32 skirts 29 are directly welded to at least some of the twelve tabs 40, for example eight tabs in this example. These 8 tabs 40
Are arranged on the four corners, the major axis and the minor axis. The remaining four tabs 40 act as vibration suppressors. The number of tabs used for support and vibration suppression may vary in some embodiments.

The frame 32 is shown with the individual tabs 40 extending from the distal end of the second flange 38, but with the integrally formed tabs 40 'as shown in FIGS. 11 and 12. 3
It may be configured to be part of a third flange 52 extending from the end of 8 '. In this alternative embodiment, the frame
32 'has a U-shaped cross section around it. FIG. 11 shows a cross section of the frame 32 'at the same position corresponding to the cross section of the frame 32 of FIG. Figure 12 shows
10 shows a cross section of the frame 32 'at the same position corresponding to the cross section of the frame 32 in FIG. In the frame 32 ', the first flange 36' is connected to the second flange 38 'in the same manner as the first flange 36 is connected to the second flange 38 in the frame 32. Third flange 52
Extends from the second flange 38 'at an angle of less than 90 ° except for the portion of the second flange 38' that forms the tab 40 '. The tab 40 'is formed by the embossed portion in the third flange 52, and
It extends vertically from 38 '.

Unlike most conventional shadow masks, the edges 27 of this shadow mask 24 are very narrow. Even with an electron beam overscan of only about 3%, the electron beam energy is sufficient to heat the edge 27. By reducing the size of the edges and limiting the contact area with the frame 32, the cold zone around the perforated portion 25 of the mask 24 can be reduced to reduce the domed ridges of the mask 24.
Further, by limiting the contact area of the skirt portion 29 with the tab 40, the skirt portion 29 can be flexed to some extent during the temperature rising period of the mask 24, thereby further reducing the mask dome-shaped protrusion. Further, the supporting structures provided at the four corners of the frame and the panel can prevent the mask-frame structure from rotating and shifting during the operation of the picture tube. Furthermore, the construction of the mask-frame assembly 30 in which the mask 24 is telescopically fitted inside the frame 32 or 32 'allows the assembly of this assembly to be performed faster and more accurately, which is more economical. Become. For example, since the tabs are parallel to the central longitudinal axis ZZ of the picture tube, the mask can fit into it from either side of the frame. Therefore, it is possible to first mount the frame in the face plate and then fit the mask into the frame from the rear side. The mask can be welded to the tabs that are easily accessible when the mask is in the proper position.

[Brief description of drawings]

FIG. 1 is a side view of a section of a color picture tube according to the present invention taken along the tube axis, and FIG. 2 is a cross section of the face plate panel of the picture tube of FIG. 1 taken along the tube axis and a mask. FIG. 3 is a top view of a part of the frame structure, and FIG.
FIG. 3 is a view showing a part of the bottom of the face plate panel and the mask-frame structure seen from FIG. 3, and FIG. 4 is a view showing a cross section and a supporting structure of a corner of the face plate panel and the frame of the picture tube of FIG. 5 is a front view of the support structure of FIG. 4, FIG. 6 is a front view of the picture tube frame of FIG. 1, and FIG. 7 is a portion of the frame taken along line 7-7 of FIG. Fig. 8 is a view showing a part of the frame as seen from line 8-8 in Fig. 6, Fig. 9 is a sectional view taken along line 9-9 in Fig. 6, and Fig. 10 is shown in Fig. 6 A sectional view along the line 10-10,
FIG. 11 is a sectional view of a frame of another embodiment corresponding to FIG. 9, and FIG. 12 is a sectional view of a frame of another embodiment corresponding to FIG. 8 ... Color picture tube, 10 ... Enclosure, 12 ... Face plate panel, 18 ... Face plate, 22 ... Cathode ray screen, 26 ... Electron gun, 32 and 32 '... Peripheral frame , 36 and 36 '…… First flange, 38 and 38 ′ ……
Second flange, 40 and 40 '... tab.

Claims (1)

[Claims] 1. A color picture tube comprising an envelope having a rectangular faceplate panel and a neck interconnected thereto; further mounted within said faceplate panel by support means. A rectangular shadow mask attached to a peripheral frame, a cathode ray emitting screen disposed on the inner surface of the face plate of the panel, and a neck portion disposed to generate a plurality of electron beams, which are used as the shadow mask. And an electron gun projecting toward the screen through the peripheral frame, the peripheral frame having first and second flanges, the first flange being substantially parallel to the central longitudinal axis of the picture tube. In a direction substantially parallel to the surface of the first flange and the center of the second flange in a direction substantially parallel to the surface of the shadow mask. The second flange further has a plurality of tabs extending toward the axis and extending along the inner edge thereof at a distance from each other in a direction substantially parallel to the central longitudinal axis. The mask is supported by the peripheral frame by mechanically contacting the plurality of tabs and being fixed to at least some of the plurality of tabs. .